For test and analysis of body tissues, a tissue array constituted by arranging a plurality of tissue pieces on a substrate is used. The tissue array is used for testing of the presence or absence of lesional tissues, analysis and screening of genes and proteins, etc. by coating or the like of a staining solution which specifically stains test article, or the like.
In relation to formation of tissue pieces constituting the tissue array, it has been general to punch a tissue block embedded with an embedding medium such as paraffin and to circularly cut out the tissue block for sampling a core.
However, according to such a method for forming the tissue pieces, there have been problems in which a particular region of interest which especially attracts attention in the lesional tissue in the tissue block may be deleted when it is sliced after sampling of the core.
Furthermore, among researchers who study body tissues, some researchers think that punching the tissue block is undesirable for the subsequent researches because the region is completely deleted from the tissue block.
Therefore, there has been examined the formation of the tissue pieces constituting the tissue array, not by the method of cutting out the circular core from the tissue block, but by another method.
Methods proposed in order to solve the above-mentioned problems are disclosed in Patent Literatures 1 and 2.
In the methods for forming tissue pieces disclosed in Patent Literatures 1 and 2, a tissue block is first sliced by a microtome or the like and a sheet-like tissue piece is obtained. Subsequently the sheet-like tissue piece is rolled up.
The rolled-up roll-shaped tissue piece is inserted into a hole of the substrate block obtained by forming an embedding medium such as paraffin into a block shape. When a predetermined number of roll-shaped tissue pieces are arranged on the substrate block, the substrate block is sliced so that the roll-shaped tissue pieces are in the form of round slices, and the slices are placed on the substrate such as a microscope slide, for the formation of a tissue array.
In addition, when the roll-shaped tissue piece is inserted into the hole of the substrate block constituted by forming the embedding medium such as paraffin into the block shape, the diameter of the roll-shaped tissue piece preferably coincides with that of the hole. This is because positioning can be securely performed by making these diameters coincide with each other.
In this way, in the formation methods described in Patent Literatures 1 and 2, various regions in a wide range of tissues can be put into one tissue piece by rolling the sheet-like tissue piece in the shape of a roll, and thus the problem of deleting the particular region of interest which especially attracts attention in the lesional tissue can be solved.
Consequently, the tissue can remain only by thinly slicing its surface without punching the tissue block and can be useful for subsequent studies.